How to integrate Heygen MCP with Pydantic AI

This guide walks you through connecting Heygen to Pydantic AI using the Composio tool router. By the end, you'll have a working Heygen agent that can create a talking photo from your selfie, add new contacts to your video project, list all available streaming avatars for today through natural language commands. This guide will help you understand how to give your Pydantic AI agent real control over a Heygen account through Composio's Heygen MCP server. Before we dive in, let's take a quick look at the key ideas and tools involved.

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HeyGen is an AI-driven video creation platform that streamlines content production. Create, edit, and automate video workflows with generative AI for faster results.

71 Tools

Introduction

This guide walks you through connecting Heygen to Pydantic AI using the Composio tool router. By the end, you'll have a working Heygen agent that can create a talking photo from your selfie, add new contacts to your video project, list all available streaming avatars for today through natural language commands.

This guide will help you understand how to give your Pydantic AI agent real control over a Heygen account through Composio's Heygen MCP server.

Before we dive in, let's take a quick look at the key ideas and tools involved.

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TL;DR

Here's what you'll learn:
  • How to set up your Composio API key and User ID
  • How to create a Composio Tool Router session for Heygen
  • How to attach an MCP Server to a Pydantic AI agent
  • How to stream responses and maintain chat history
  • How to build a simple REPL-style chat interface to test your Heygen workflows

What is Pydantic AI?

Pydantic AI is a Python framework for building AI agents with strong typing and validation. It leverages Pydantic's data validation capabilities to create robust, type-safe AI applications.

Key features include:

  • Type Safety: Built on Pydantic for automatic data validation
  • MCP Support: Native support for Model Context Protocol servers
  • Streaming: Built-in support for streaming responses
  • Async First: Designed for async/await patterns

What is the Heygen MCP server, and what's possible with it?

The Heygen MCP server is an implementation of the Model Context Protocol that connects your AI agent and assistants like Claude, Cursor, etc directly to your Heygen account. It provides structured and secure access to your Heygen video platform, so your agent can perform actions like creating talking photos, managing video assets, personalizing video projects, and controlling streaming avatars on your behalf.

  • AI-powered video asset creation: Add new avatars, backgrounds, or other content elements directly into your Heygen library for use in video generation workflows.
  • Personalized video project management: Let your agent add contacts to personalized video projects and fetch detailed project information to streamline large-scale video personalization efforts.
  • Dynamic talking photo generation: Instantly create engaging talking photos from uploaded images, transforming static pictures into interactive, speaking content for marketing or educational use.
  • Real-time avatar streaming control: Retrieve a list of streaming avatars, generate streaming tokens, and manage live avatar sessions—including interrupting or monitoring ongoing streams for responsive, interactive experiences.
  • Audience insights and analytics: Fetch detailed audience engagement and preference data for personalized video campaigns, helping you optimize your content and targeting strategies.

What is the Composio tool router, and how does it fit here?

What is Composio SDK?

Composio's Composio SDK helps agents find the right tools for a task at runtime. You can plug in multiple toolkits (like Gmail, HubSpot, and GitHub), and the agent will identify the relevant app and action to complete multi-step workflows. This can reduce token usage and improve the reliability of tool calls. Read more here: Getting started with Composio SDK

The tool router generates a secure MCP URL that your agents can access to perform actions.

How the Composio SDK works

The Composio SDK follows a three-phase workflow:

  1. Discovery: Searches for tools matching your task and returns relevant toolkits with their details.
  2. Authentication: Checks for active connections. If missing, creates an auth config and returns a connection URL via Auth Link.
  3. Execution: Executes the action using the authenticated connection.

Step-by-step Guide

Step by step09 STEPS
1

Prerequisites

Before starting, make sure you have:
  • Python 3.9 or higher
  • A Composio account with an active API key
  • Basic familiarity with Python and async programming
2

Getting API Keys for OpenAI and Composio

OpenAI API Key
  • Go to the OpenAI dashboard and create an API key. You'll need credits to use the models, or you can connect to another model provider.
  • Keep the API key safe.
Composio API Key
  • Log in to the Composio dashboard.
  • Navigate to your API settings and generate a new API key.
  • Store this key securely as you'll need it for authentication.
3

Install dependencies

bash
pip install composio pydantic-ai python-dotenv

Install the required libraries.

What's happening:

  • composio connects your agent to external SaaS tools like Heygen
  • pydantic-ai lets you create structured AI agents with tool support
  • python-dotenv loads your environment variables securely from a .env file
4

Set up environment variables

bash
COMPOSIO_API_KEY=your_composio_api_key_here
USER_ID=your_user_id_here
OPENAI_API_KEY=your_openai_api_key

Create a .env file in your project root.

What's happening:

  • COMPOSIO_API_KEY authenticates your agent to Composio's API
  • USER_ID associates your session with your account for secure tool access
  • OPENAI_API_KEY to access OpenAI LLMs
5

Import dependencies

python
import asyncio
import os
from dotenv import load_dotenv
from composio import Composio
from pydantic_ai import Agent
from pydantic_ai.mcp import MCPServerStreamableHTTP

load_dotenv()
What's happening:
  • We load environment variables and import required modules
  • Composio manages connections to Heygen
  • MCPServerStreamableHTTP connects to the Heygen MCP server endpoint
  • Agent from Pydantic AI lets you define and run the AI assistant
6

Create a Tool Router Session

python
async def main():
    api_key = os.getenv("COMPOSIO_API_KEY")
    user_id = os.getenv("USER_ID")
    if not api_key or not user_id:
        raise RuntimeError("Set COMPOSIO_API_KEY and USER_ID in your environment")

    # Create a Composio Tool Router session for Heygen
    composio = Composio(api_key=api_key)
    session = composio.create(
        user_id=user_id,
        toolkits=["heygen"],
    )
    url = session.mcp.url
    if not url:
        raise ValueError("Composio session did not return an MCP URL")
What's happening:
  • We're creating a Tool Router session that gives your agent access to Heygen tools
  • The create method takes the user ID and specifies which toolkits should be available
  • The returned session.mcp.url is the MCP server URL that your agent will use
7

Initialize the Pydantic AI Agent

python
# Attach the MCP server to a Pydantic AI Agent
heygen_mcp = MCPServerStreamableHTTP(url, headers={"x-api-key": COMPOSIO_API_KEY})
agent = Agent(
    "openai:gpt-5",
    toolsets=[heygen_mcp],
    instructions=(
        "You are a Heygen assistant. Use Heygen tools to help users "
        "with their requests. Ask clarifying questions when needed."
    ),
)
What's happening:
  • The MCP client connects to the Heygen endpoint
  • The agent uses GPT-5 to interpret user commands and perform Heygen operations
  • The instructions field defines the agent's role and behavior
8

Build the chat interface

python
# Simple REPL with message history
history = []
print("Chat started! Type 'exit' or 'quit' to end.\n")
print("Try asking the agent to help you with Heygen.\n")

while True:
    user_input = input("You: ").strip()
    if user_input.lower() in {"exit", "quit", "bye"}:
        print("\nGoodbye!")
        break
    if not user_input:
        continue

    print("\nAgent is thinking...\n", flush=True)

    async with agent.run_stream(user_input, message_history=history) as stream_result:
        collected_text = ""
        async for chunk in stream_result.stream_output():
            text_piece = None
            if isinstance(chunk, str):
                text_piece = chunk
            elif hasattr(chunk, "delta") and isinstance(chunk.delta, str):
                text_piece = chunk.delta
            elif hasattr(chunk, "text"):
                text_piece = chunk.text
            if text_piece:
                collected_text += text_piece
        result = stream_result

    print(f"Agent: {collected_text}\n")
    history = result.all_messages()
What's happening:
  • The agent reads input from the terminal and streams its response
  • Heygen API calls happen automatically under the hood
  • The model keeps conversation history to maintain context across turns
9

Run the application

python
if __name__ == "__main__":
    asyncio.run(main())
What's happening:
  • The asyncio loop launches the agent and keeps it running until you exit

Complete Code

Here's the complete code to get you started with Heygen and Pydantic AI:

python
import asyncio
import os
from dotenv import load_dotenv
from composio import Composio
from pydantic_ai import Agent
from pydantic_ai.mcp import MCPServerStreamableHTTP

load_dotenv()

async def main():
    api_key = os.getenv("COMPOSIO_API_KEY")
    user_id = os.getenv("USER_ID")
    if not api_key or not user_id:
        raise RuntimeError("Set COMPOSIO_API_KEY and USER_ID in your environment")

    # Create a Composio Tool Router session for Heygen
    composio = Composio(api_key=api_key)
    session = composio.create(
        user_id=user_id,
        toolkits=["heygen"],
    )
    url = session.mcp.url
    if not url:
        raise ValueError("Composio session did not return an MCP URL")

    # Attach the MCP server to a Pydantic AI Agent
    heygen_mcp = MCPServerStreamableHTTP(url, headers={"x-api-key": COMPOSIO_API_KEY})
    agent = Agent(
        "openai:gpt-5",
        toolsets=[heygen_mcp],
        instructions=(
            "You are a Heygen assistant. Use Heygen tools to help users "
            "with their requests. Ask clarifying questions when needed."
        ),
    )

    # Simple REPL with message history
    history = []
    print("Chat started! Type 'exit' or 'quit' to end.\n")
    print("Try asking the agent to help you with Heygen.\n")

    while True:
        user_input = input("You: ").strip()
        if user_input.lower() in {"exit", "quit", "bye"}:
            print("\nGoodbye!")
            break
        if not user_input:
            continue

        print("\nAgent is thinking...\n", flush=True)

        async with agent.run_stream(user_input, message_history=history) as stream_result:
            collected_text = ""
            async for chunk in stream_result.stream_output():
                text_piece = None
                if isinstance(chunk, str):
                    text_piece = chunk
                elif hasattr(chunk, "delta") and isinstance(chunk.delta, str):
                    text_piece = chunk.delta
                elif hasattr(chunk, "text"):
                    text_piece = chunk.text
                if text_piece:
                    collected_text += text_piece
            result = stream_result

        print(f"Agent: {collected_text}\n")
        history = result.all_messages()

if __name__ == "__main__":
    asyncio.run(main())

Conclusion

You've built a Pydantic AI agent that can interact with Heygen through Composio's Tool Router. With this setup, your agent can perform real Heygen actions through natural language. You can extend this further by:
  • Adding other toolkits like Gmail, HubSpot, or Salesforce
  • Building a web-based chat interface around this agent
  • Using multiple MCP endpoints to enable cross-app workflows (for example, Gmail + Heygen for workflow automation)
This architecture makes your AI agent "agent-native", able to securely use APIs in a unified, composable way without custom integrations.
TOOLS

Supported Tools

Every Heygen action and event your agent gets out of the box.

Add looks to photo avatar group

Tool to add additional looks (images) to an existing photo avatar group.

Add motion to photo avatar

Tool to add natural motion or animation to an existing photo avatar, turning a still image into a moving, lifelike one.

Check photo/look generation status

Tool to retrieve the current status and details of a photo avatar or look generation by its ID.

Create a new folder

Tool to create a new folder under your HeyGen account.

Create knowledge base

Tool to create a new knowledge base with a specified name, opening line, and custom prompt for Interactive Avatar streaming sessions.

Create photo avatar group

Tool to create an avatar group which can include both AI-generated and user-uploaded photos of the avatar.

Create WebM video

Tool to create a WebM format video with transparent background featuring an avatar speaking text or audio.

Delete an avatar video

Tool to delete a video by its ID from HeyGen account.

Delete asset

Tool to delete a specific asset by its unique asset ID from HeyGen account.

Delete knowledge base

Tool to delete a specific knowledge base by its ID.

Delete photo avatar

Tool to delete a photo avatar by its ID from HeyGen account.

Delete photo avatar group

Tool to delete a photo avatar group by its ID from HeyGen account.

Delete webhook endpoint

Tool to permanently delete a webhook endpoint from HeyGen.

Generate photo avatar photos

Tool to generate a personalized AI avatar based on text prompts and attribute inputs.

Generate text-to-speech audio

Tool to generate a speech audio file from any text input using a specified voice, powered by HeyGen's Starfish model.

Generate voice audio preview

Tool to generate a short audio preview with the specified voice and text.

Get current user information

Tool to retrieve the profile information of the currently authenticated user.

Get training job status

Tool to retrieve the current training status and details of a photo avatar training job by group ID.

Keep alive streaming session

Tool to reset the idle timeout counter for an active streaming session.

List all avatar groups

Tool to retrieve a list of all available avatar groups in your HeyGen account.

List all locales for voices

Tool to retrieve available locales for multilingual voices.

List assets

Tool to retrieve a paginated list of all assets (images, audios, videos) created under your account.

List brand voices

Tool to retrieve a list of brand glossaries created under your account.

List folders

Tool to retrieve a paginated list of folders created under your account.

List avatars in a specific group

Tool to retrieve all avatars that belong to a specific avatar group.

List knowledge bases

Tool to retrieve a list of all existing knowledge bases associated with your account.

List session history

Tool to retrieve a paginated history of all streaming sessions with metadata including session duration, timestamps, and other details.

List streaming avatars

Tool to retrieve a list of public and custom interactive avatars for streaming.

List TTS voices

Tool to retrieve a list of public and custom voices compatible with HeyGen's Starfish TTS model.

Create new streaming session

Tool to initiate a new streaming session with an Interactive Avatar for real-time interactions.

Add contact to personalized video project

This endpoint allows you to add one or more contacts to a specific personalized video project in the Heygen platform.

Fetch personalized video project detail

Retrieves detailed information about a specific personalized video project in HeyGen, including status, settings, and metadata.

Get photo avatar details

Tool to retrieve detailed information about a photo avatar or look using its unique ID.

Post talking photo binary image

Creates a talking photo by processing an uploaded image file.

Restore folder from trash

Tool to restore a previously deleted folder from trash by its unique folder ID.

Retrieve avatar details

Tool to retrieve detailed information about a specific avatar by its ID.

Retrieve sharable video URL

Tool to generate a public, shareable URL for a specific video by ID.

Retrieve template details v3

Tool to retrieve comprehensive details about a specific template including all available variables for replacement and scene mappings for templates built in the New AI Studio.

Retrieve video status details

Tool to retrieve the current processing status and metadata for a specific video by ID.

Search public avatar groups

Tool to search and retrieve public avatar groups with optional filters and pagination.

Create streaming token with expiry

Creates a new streaming token for use with HeyGen's real-time avatar and voice chat services.

Post streaming ice candidates

This endpoint is used to submit ICE (Interactive Connectivity Establishment) candidate information for a specific streaming session in the Heygen platform.

Interrupt streaming session

Interrupts an ongoing streaming session with an interactive avatar.

Retrieve streaming list

Retrieves a list of active or available streaming sessions or content within the HeyGen platform.

Set streaming quality endpoint

Initiates a new streaming session with HeyGen, allowing users to start an avatar-based stream with specified quality settings.

Start streaming session

Initiates a new streaming session for real-time communication in the HeyGen platform.

Stop streaming session

The streaming.

Send task to streaming avatar

The StreamingTask endpoint initiates a real-time speaking task for an AI-driven avatar within an active streaming session.

Move folder to trash

Tool to move a specific folder to trash by its unique folder ID.

Update folder name

Tool to update (rename) an existing folder by its unique folder ID.

Update knowledge base

Tool to update an existing knowledge base by its ID.

Update webhook endpoint

Tool to modify an existing webhook endpoint configuration including URL and subscribed event types.

Upload asset

Tool to upload a file asset (image, video, or audio) to HeyGen platform.

Upscale motion avatar

Tool to enhance the resolution and visual quality of a motion avatar.

List avatars endpoint

Retrieves a list of available avatars from the Heygen platform.

List talking photo entries

Retrieves a list of talking photos created using the HeyGen platform.

List videos

Retrieves a list of videos associated with the user's account on the HeyGen platform.

List voice endpoints

Retrieves a comprehensive list of all available voices in the HeyGen platform.

Add webhook endpoint

Adds a new webhook endpoint to receive real-time notifications for specified Heygen events.

List webhook endpoints

Retrieves a list of all webhook endpoints configured for your HeyGen account.

List webhooks

Retrieves a list of all available webhook event types that can be subscribed to in your HeyGen account.

Delete talking photo by id

Deletes a specific talking photo from the HeyGen platform using its unique identifier.

Generate video template with variables

Generates a customized video from a pre-existing template using HeyGen's AI platform.

Get template by id

Retrieves a specific template from the HeyGen platform using its unique identifier.

Retrieve all templates

Retrieves a list of available avatar templates from the HeyGen platform.

Retrieve user remaining quota

Retrieves the current remaining quota for the authenticated user on the HeyGen platform.

Generate video with inputs

Generates a customized video using Heygen's AI-driven platform.

Post video translate request

The TranslateVideo endpoint enables the translation of video content from one language to another.

Retrieve video translation by id

Retrieves the current status of a video translation job in the HeyGen platform.

Retrieve video translation target languages

Retrieves a list of all available target languages supported by HeyGen's video translation feature.

List available voices

Retrieves a list of available voice models and options that can be used with HeyGen's AI-driven video creation platform.

FAQ

Frequently asked questions

With a standalone Heygen MCP server, the agents and LLMs can only access a fixed set of Heygen tools tied to that server. However, with the Composio Tool Router, agents can dynamically load tools from Heygen and many other apps based on the task at hand, all through a single MCP endpoint.

Yes, you can. Pydantic AI fully supports MCP integration. You get structured tool calling, message history handling, and model orchestration while Tool Router takes care of discovering and serving the right Heygen tools.

Yes, absolutely. You can configure which Heygen scopes and actions are allowed when connecting your account to Composio. You can also bring your own OAuth credentials or API configuration so you keep full control over what the agent can do.

All sensitive data such as tokens, keys, and configuration is fully encrypted at rest and in transit. Composio is SOC 2 Type 2 compliant and follows strict security practices so your Heygen data and credentials are handled as safely as possible.

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